A method of this type is known from U.S. Pat. No. 6,837,091. In this case, a first end portion of the tube is reduced freely in external diameter in a matrix without internal support, a middle tube portion having lesser wall thickness and larger external diameter is manufactured by stretching over an internal mandrel of constant diameter, and a second end portion of the tube is manufactured through reduction in external diameter in a matrix in the opposite drawing direction or through hammering without internal support.
A method of the type cited, in which a first portion of a tube is reduced over a calibration mandrel which is introduced from the tube end discussed, and in which an intermediate portion of the tube is reduced over a stretching mandrel, which is introduced from the other tube end, is known from DE 35 06 220 A1. The second end portion of the tube is reduced over the calibration mandrel again after changeover of the tube. The stretching mandrel comprises two longitudinal sections of different diameters having a conical transition area.